<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>相对定位</title>
    <style>
    .c1{
        background-color: red;
    }
    
    
    
    </style>

</head>

<body>
    <div id="c1">
        1
    </div>
    <div id="c2">
        2
    </div>
    <div id="c3">
        3
    </div>
    <div id="c4">
        4
    </div>
    <div id="5">
        5
    </div>
</body>

</html>